Communication cables formed of fiber optics are pulled through trunking systems for installation. During the pulling operation the cables are subjected to rotational and tensional loads which are caused by resistance created by the configuration of the trunking path or by obstructions therein. An excessive pulling force will result in an elongation of the cable causing an excess in the admissible tension which can be taken by the fiber optics in the cable. This pulling force may also be caused by a torsion of the cable as the latter is being pulled.